When skies are gray and everything’s wrong, I’ll get by, just on a song -- Banu Gibson singing a Louis Armstrong composition.

Banu Gibson removed a soggy song list from a music stand, stepped to the edge of the stage and squeezed the rainwater out of the forlorn wad of paper. Twenty minutes earlier a chilly spring deluge had swept across Jackson Square, dousing the stage – despite the tent that covered it -- with water and sending Gibson’s fans scurrying for cover. As gusts of wind scoured the crepe myrtles, Gibson’s band retreated to the rear of the stage, watching the water roll off of the tent flaps and waiting for word if the show would go on.

Weather wise, it had been a sword of Damocles start for French Quarter Fest 2013, with continuous cloud cover and tornado threats through Thursday morning. When Gibson’s show began at half-past noon and it still seemed possible that the rain would hold off. Wearing a beatnik-style black and white striped pullover, the auburn haired singer launched into Louis Armstrong’s “I Got a Heart Full of Rhythm.” Simultaneously, streaks of silver began slicing through the sky and umbrellas began popping like colorful mushroom caps. The refrain of the first song was prophetic.

“When skies are gray and everything’s wrong, I’ll get by, just on a song,” Gibson sang.

Gibson is a traditionalist. Her French Quarter Fest set was studded with jazz-era gems made famous by Bessie Smith, Billie Holiday and Ella Fitzgerald. Her voice is clear. Her phrasing is precise. Like a master chef, Gibson expertly served up every delectably witty lyric. It was during the closing bars of a very early Judy Garland hit “Swing Mr. Charlie” that the sword of precipitation finally fell.

Wires and water were everywhere on the stage. But considering everything, spirits were high. Gibson pointed out one dedicated French Quarter Fest fan that’d held fast in a folding chair beneath an inadequate tree as the rain pelted her.

Sometime during the antediluvian part of the show, Gibson had introduced Bobby Havens a venerable trombonist who had once played with Lawrence Welk’s orchestra – specializing in Dixieland performances. It was one of those six-degrees-of-separation moments that improbably linked the mellow television maestro Lawrence Welk (1903-1992) with rough and ready rock n’ roll drummer Levon Helm (1940-2012). Gibson and Helm opened a short-lived French Quarter nightclub together more than a decade ago. As occasional thunderclaps boomed overhead, Gibson recalled that Helm was a likable, down to earth sort of character. She and he used to swap stories, she said.

In time the rain quit. A man in a yellow jacket squeegeed water off of the stage. Musicians did their best to gather limp sheet music. The plastic-coated crowd reappeared out of nowhere and the show was back on track. A couple danced to the boogie-woogie of the final song on the wet pavement. Inconsiderate droplets fell from time to time.

“Baby,” Gibson belted, “what’s on your worried mind?”

“Baaaaaby, what’s on your worried mind?”

Look for a video of the rain-interupted performance tomorrow on NOLA.com